The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Full-vehicle crash testing has been proposed previously, and indeed is still widely used, to reproduce the dynamic conditions of vehicle accidents in a controlled testing environment. These tests involve the destruction of substantially complete motor vehicles and so they are complex and expensive to conduct. Also, engineering analysis typically requires multiple tests to be conducted so that occupant motion and vehicle structure comparisons can be made between tests, thereby requiring several vehicles to be destroyed. Whilst full-vehicle crash tests of this type are still important, it has thus become common to use so-called sled-tests to simulate the conditions of a full-scale crash test in a controlled environment.
A particular advantage of sled testing is that it avoids the need to destroy real vehicles, and can be conducted in a more readily repetitive manner and at significantly reduced cost. Typically, a simulated occupant compartment of a motor vehicle, generally referred to as a “vehicle buck”, is mounted to a test sled carriage. The buck and sled carriage are then subjected to decelerations representative of a particular vehicle crash scenario. This controlled deceleration is commonly referred to as a sled pulse and is modelled from accelerometer data obtained from actual full-scale crash tests.
Current sled test apparatus and associated test methods are restricted to the assumption that no deformation of the vehicle structure or intrusion into the occupant compartment (i.e. the cabin space) takes place. The practical effect of this assumption is that in certain crash scenarios the sled test method can provide false crash data. There is therefore a need to provide a sled test apparatus and associated test method which can simulate intrusion into the vehicle cabin.
Document DE102008031659 discloses a carriage for carrying out crash tests on motor subassemblies having a first carrier for carrying a motor vehicle component to be tested, wherein the carriage is designed to be moved relative to a stop unit with the result that the carriage can collide with the stop unit, and wherein the first carrier is movably mounted to the carriage such that it is moved along a predetermined path if the carriage collides with the stop unit.
Document DE19894856 discloses a side impact simulation plant for simulating intrusions and accelerations of vehicle side structures into the vehicle inner as well as the accelerations of an entire vehicle upon a side impact.
Document US2008/0034902 discloses a sled carriage configured to move in the direction of an axis. A platform is attached with the sled carriage and a sled buck is attached with the platform. Upon accelerations of the carriage, the sled buck and platform move relative to the sled carriage.
A passenger car frontal impact involving the engagement of ⅓ or less of the car's full width with another object such as a barrier is generally defined as a “small overlap” (or “off-set”) impact. Such impacts often result in severe car structure deformations and severe injuries for the nearside occupants. Indeed it has been found that approximately 25% of all fatal frontal accidents involving occupants restrained by safety belts in passenger cars are small overlap impacts of this type, and these often occur on roads with speed limits over 60 km/h.
In frontal impact situations involving larger overlap between the width of the vehicle and the obstacle (for example ⅓ to ½ of the vehicle width), the vehicle structure normally deforms much less relative to the small overlap case. This is because the load distribution area is larger and also because modern passenger cars are generally optimized for this load situation due to being designed in response to data from standard crash tests.
When the longitudinal load transferring structure of the passenger car is not fully engaged with the obstacle upon impact, as would be the case in a small overlap impact, and the resulting deformation of the vehicle structure occurs close to the occupant, there is a significantly increased risk of injury to the occupant from cabin intrusion. In nearside impacts of this type, the car structure in front of the occupant starts to move inwards relative the cabin, and the lower A-pillar of the car which is engaged by the nearside wheel intrudes into the cabin, followed by the upper A-pillar, the crossbeam and the dashboard. The steering wheel, which is connected to the crossbeam or dashboard, moves longitudinally inwardly, vertically upwardly and laterally into the compartment. The intrusion of the dashboard is such that it typically rotates relative to the A-pillar on the opposite side of the vehicle. There is currently no sled-test apparatus or method which can reliably simulate the conditions of this type of cabin-intrusion scenario.